Sacrificial template synthesis of short mesoporous NiO nanotubes and their application in electrochemical capacitors

We developed a sacrificial template strategy to synthesize short NiO nanotubes (S-NiO NTs) with mesopores in sidewalls by using short carbon NTs as template for electrochemical capacitors. Further physical characterizations exhibited that as-synthesized S-NiO NTs owned a specific surface area of 150 m(2) g(-1) and hierarchical (meso- and macro-) porosity. Electrochemical data presented that such NTs delivered a specific capacitance of 903 Fg(-1) at 1 Ag-1, much larger than those of long NiO NTs and NiO nanoparticles. The capacity retention of ca. 88%, when the current density increased from 1 to 4 Ag-1, indicated high rate capability of the unique S-NiO NTs electrode. Furthermore, a capacitance degradation of ca. 6% after 2000 charge-discharge cycles at 4 A g(-1) demonstrated their desirable electrochemical stability. The short tubular and hierarchical porous feature of the S-NiO NTs resulted in the high electrochemical utilization for energy storage even at high rates. (C) 2012 Elsevier Ltd. All rights reserved.